Oil made each Osage headright worth a fortune, at least 24 Osage were killed in the early 1920s, and Congress stopped non-Osage from inheriting headrights in 1925

Under the Osage Allotment Act of 1906 the tribe owned the minerals under its land in common. Each allottee held an equal share of the oil royalties, called a headright, and a headright passed to the holder's heirs. Non-Osage could inherit one. The tribe earned more than $30 million in 1923. The Oklahoma Historical Society counts about 24 Osage who died violent or suspicious deaths in the early 1920s, mostly near Fairfax; the Osage Nation counts more than 60 mysterious or unsolved murders of headright holders between 1920 and 1925. Lizzie Kyle died in July 1921, poison suspected. Anna Brown was shot in May 1921. Henry Roan was killed in January 1923; the rancher and banker William K. Hale held a $25,000 insurance policy on his life. In March 1923 a bomb destroyed the house of Rita and Bill Smith, killing them and their housekeeper. The Osage Tribal Council asked for federal help, and Bureau of Investigation agents arrested Hale, Ernest Burkhart and John Ramsey in January 1926. Burkhart pleaded guilty to the Smith murders and testified. Hale and Ramsey got life sentences in 1929 for killing Roan. All three were paroled; Governor Henry Bellmon pardoned Burkhart in 1965. In 1925 Congress barred non-Osage from inheriting the headrights of members with more than half Osage blood. In 2014 the Osage Minerals Council wrote to non-Osage headright holders asking them to give their shares back or sell them to the Council.